1. Field of the Invention
The present invention relates to a round baler including a front housing, a rear housing pivotally connected with the front housing, an upper axle secured in the front housing and supporting the rear housing for a pivotal movement relative to the front housing, and locking means for latching the rear housing to the front housing in a closed operational position of the rear housing and releasable upon a pressure acting on the rear housing reaching a predetermined value.
2. Description of the Prior Art
German Publications DE 24 43 838A1 and DE 31 18 663A1 disclose mechanical locking devices for latching the front and rear housings. The rigid latching insures obtaining of high compression densities and uniform diameters of bales. In order to protect the drives of the compression elements and the compression elements themselves from overload, conventionally, a safety shear bolt, a friction clutch, or an automatically actuated cam decoupler is used in the main drive train of the baler. The actuation of a tying device is effected usually manually or automatically upon a predetermined pressure having been reached. The big drawback of balers equipped with the above-discussed over-load protection means consists in that when, upon shearing of the safety bolt, actuation of the friction or cam clutch, or upon sliding of the compression elements relative to a bale circumference, the bale remains, in particular at unfavorable crop conditions, in the compression chamber, the not yet tied bale cannot be set in rotation again without preliminary delatching the front and rear housings. Because of a large expansion force of the compressed material of the bale, the rear housing should be pivoted out by 30-50 cm. The large opening path of the rear housing results in that the bale has an overlarge diameter and cannot be tied up or can be tied up only partially. Practically, it means that it is necessary to compress the defective bale anew.
In a round baler produced by a firm Claas, type Rollant 66,46 silage 46 Roto Cut, pressure head 8/95, the front and rear housings are hydraulically latched. To protect the compression chamber from overload, a hydraulic overload protection device is provided which, upon the compression density exceeding a predetermined value, has its pressure limiting value actuated which results in bleeding of the oil off and in opening of the rear housing. The drawback of this type of protection consists in that the openings path of the rear housing is not limited, resulting in producing overlarge, not completely bound bales. There is no possibility of securing the rear housing in a closed position in which it would prevent an uncontrolled expansion of the bale. This is because the pressure limiting valve does not permit to obtain the necessary high closing pressure.
Accordingly, an object of the present invention is to provide a round baler which would insure finishing the formation of a bale, i.e., its tying up despite the stoppage of formation of the bale in the compression chamber, i.e., would insure tying of the bale and its ejection.
Another object of the present invention is to provide a round baler which would insure obtaining, after a stoppage of the baler, a bale diameter which is substantially the same as a bale diameter obtained during normal operation of the baler.
These and other objects of the present invention, which would become apparent hereinafter, are achieved by providing a round baler the locking means of which includes means for latchingly connecting the front and rear housings in a partially open position of the rear housing. Research and practice have shown that a small, limited opening of the housing by about from 20 to about 100 mm is sufficient to provide for resumption of rotation of a bale and maintaining the rotation during tying-up of the bale because the reduction of the load of the compression elements, the reduction of the rolling resistance of the bale, and multiple overrunning of the bale by the compression elements at insufficient delivery of the crop provide for reduction of the bale diameter. A further advantage of the present invention consists in that the rear housing can again be pulled to its initial closing position during the tying-up process. This is possible because the bale expands by a relatively small amount as a result of the small, limited opening of the rear housing.
A constructionally simple locking device, which permits both a limited opening of the rear housing and its closing, includes, in accordance with the present invention, a locking pawl and a latching member cooperating with the locking pawl and formed as a rotatable eccentric or a rotatable cam rotatable between a first position, in which the rear housing is connected with the front housing in the closed position of the rear housing, and a second position in which the rear housing is connected with the front housing in the partially open position of the rear housing. Alternatively, the locking pawl-supporting axle can be formed as a rotable eccentric or a rotable cam. The latching member can be rotate manually, electrically, or hydraulically and be so dimensioned that it would provide for an opening distance from about 20 mm to about 40 mm.
In accordance with another embodiment of a locking device of the present invention, the locking device includes two pairs of locking pawls provided on opposite sides of the compression chamber. A locking nose of one of the locking pawls of each pair of locking pawls is offset, in the opening direction of the rear housing, with respect to a locking nose of another of the locking pawls of the pair by a distance corresponding to a desired distance the rear housing is to be moved by into its partially open position. During the normal operation of the baler, the locking pawl with the offset locking nose is located outside of the operational region of the latching member. The locking pawl with the offset locking nose is brought into a position, in which it cooperates with the latching member, only during a defective operation. It engages the latching member after the first locking pawl has been released and the rear housing has been pivoted to its partially open position. The locking pawl with the offset locking nose is released after the formation of a bale, including tying-up, has been finished, thus providing for complete openings of the rear housing and ejection of the finished bale.
In a particular advantageous embodiment of locking device according to the present invention, there is provided means which displaces the rear housing after its partial opening into the original closed position. This permits to resume rotation of the bale after its stoppage and insures obtaining of a bale diameter corresponding to a predetermined bale diameter.
The novel features of the present invention, which are considered as characteristic for invention, are set forth in the appended claims. The invention itself, however, both as to its construction and its mode of operation, together with additional advantages and objects thereof, will be best understood from the following detailed description of preferred embodiments, when read with reference to the accompanying drawings.